Method of making lined cartons



April 1964 c. D. STRIPLIN ETAL 3,130,649

METHOD OF MAKING LINED CARTONS 2 Sheets-Sheet 1 Filed Dec. 11, 1961INVENTORS GHARL ES 0. .STR/PL/IV U MO/VROE F. SMITH ATTORNEY April 28,1964 c. D. STRIPLIN ETAL 3,130,649

METHOD OF MAKING LINED CARTONS Filed Dec. 11, 1961 2 Sheets-Sheet 2 ,28[IIIIHHIHIL llllllllllllll I 1 55.4 25 kzo Y 42 Fig 6 ,NVENTORS 32CHARLES D. STRIPL/IV MONROE 7". 8M! Th f T ATTORNEY United States Patent3,136,649 METHGD OF MAKENG LINER) CARTGNS Charles D. Striplin, Concord,and Monroe F. rnith, Walnut Creek, Caiih, assignors to Fibreboard PaperProducts Corporation, San Francisco, Calif., a corporation of DelawareFiled Dec. 11, 1961, Ser. No. 158,2$9 4 Claims. (Cl. 9336.01)

This invention relates to a lined carton and to the method of making thesame and particularly to a carton made of paperboard or the like andlined with a paperlike liner.

Lined cartons having the general characteristics of that of the presentinvention are well known for the purpose of packaging foods or othermaterials which require a barrier against moisture, gas odors and thelike. A heat scalable material is used as or in conjunction with thelining and after the carton is filled, its ends are closed by heatsealing. Such cartons are generally made in a tubular flat fold form ofpaperboard with a tubular liner of similar form also folded fiat withinthe paperboard structure and pasted thereto. The fiat folded carton andliner is shipped in quantity to a food packer who sets it up, fills it,closes and seals its ends.

Heretofore there have been two methods most widely used for making suchfiat fold lined cartons. One method comprises forming a tube of theliner material from a web and heat sealing the seam thereof. The tube soformed is cut to proper lengths and secured within the carton as it isfolded from a fiat blank to its tubular shape. This method has thedisadvantage that the tubular liner is difiicult to control in highspeed machines and becomes wrinkled within the carton with the resultthat it fits poorly particularly in the corners of the carton. Oftensuch a liner bridges the corners so that it is easily ruptured in use.

Another method more easily practiced with high speed machines comprisespasting together a carton blank and sheet of lining material in flatform, then folding them into a flat fold tube simultaneously. The edgesto be secured together in the formation of the tube may then be securedwith an ordinary adhesive. The ordinary liquid adhesive which is appliedwithout heat is undesirable as a securing means for the liner which maybe a plastic film, a polyethylene coated paper or other heat sensitivematerial. A defective seam results in the liner and the joint does nothave the barrier qualities of the film material. The use of conventionalheat scaling for a lined carton formed by the later method has also beenfound unde sirable because the heat must be applied through thepaperboard of the carton on one of the larger walls thereof which isprinted for advertising and display purposes. The beat sometimesdiscolors the paperboard, may cause wax to melt and be damaged or maydiscolor or damage lacquers or inks. The resulting carton would then beunacceptable for its intended purpose.

It is an object of the present invention to provide a lined carton and amethod of mflcing the same which overcome the above mentioneddisadvantages and in which a heat scalable lining material is securelyand perfectly arranged within the carton with a heat or flame sealedseam accomplished without detrimental effect to the appearance of thecarton.

Further and more specific objects and advantages of the invention andthe manner in which it is practiced are made apparent in the followingspecification wherein reference is made to the accompanying drawings.

In the drawings:

FIG. 1 is a schematic view in side elevation of apparatus for formingsheets of line-r material for the carton "ice of the present inventionand combining them with preeut and prescored carton blanks;

PEG. 2 is a plan view of the apparatus shown in FIG. 1;

FIG. 3 is a plan view of a typical carton blank and liner thereforadhesively secured thereto in accordance with the present invention;

FIG. 4 is an edge view of the carton blank and liner viewed as from thelower edge of FIG. 3;

FIG. 5 is a view similar to FIG. 4 but showing the canton blank inpartially folded condition; and

FIG. 6 is a similar view showing the carton in substantially full flatfolded position which is its completed form prior to opening, fillingand sealing by a user.

Referring first to FIG. 1 of the drawings, a roll of liner material foruse in cartons is shown at 10. The particular material employed forlining the carton of the present application is paper having apolyethylene coating on one side. Although this particular liningmaterial is not essential to the invention at least one side or portionsthereof should be formed of a material subject to being heat sealed atthe side seam and at each end. The polyethylene or plastic coatedsurface of the sheet being withdrawn from the roll 19 faces downwardlyand passes first beneath a glue wheel shown at 11 in FIGS. 1 and 2 whichis of conventional construction and deposits a strip of glue shown at 12in FIG. 2 adjacent one edge of the paper surface side of the sheet priorto its entering a folder 13 which folds the extreme edge of the sheetinwardly upon itself and over the strip of glue 12 which secures thefold in place.

A hot melt eXt-ruder or other hot melt adhesive application equipment,the nozzle or applicator of which is shown at 14, underlies the oppositeedge of the sheet 10 to deposit a strip or bead of heat softenablematerial in the position indicated in dotted lines at 15 directlyadjacent the edge of the sheet. The hot melt material is composed offused plastic and is commercially available in varying compositions foruse with difllerent types of plastics. It is characterized by itsability to set and form a strip or head on a plastic surface which latermay be softened or melted by the application of heat to form a seal withthe lining material. When the web from the roll 10 has been so treated,it is passed bet-ween the nip of a cutter roll 16 and a vacuum roll 17and spaced knives 18 on the cutter roll cut the strip into suitablelengths which are held by the vacuum roll until they come in contactwith and are pasted to carton blanks shown at Zil as they pass betweenthe nip of the vacuum roll and a pressure roll 22. The carton blanks 2%have previously been fed beneath a glue roll 23 which applies glue tothe blanks in a pattern presently to be described so that the blanks andliners are securely held together after passing between the vacuum rolland the pressure roll and are then delivered to a folder in which theyare folded to a flat fold tubular form.

A combined blank and liner such as issues from between the nip of thevacuum roll and pressure roll of FIG. 1 is illustrated in FIG. 3 whereinthe carton blank 2 is illustrated as lying beneath a sheet of linermaterial 25. The carton blank is of a conventional type designed toprovide a rectangular carton having two large and two small panelsdivided by parallel score lines which are shown as four in number at 26.Score lines 28 disposed at right angles to the score lines 26 separateend tabs adjacent opposite ends of the four panels which form the fourmain walls of the carton and these end tabs serve to close the ends ofthe carton in a well known manner. Their particular configuration andconstruction will not be referred to herein in further detail as itforms no part of the present invention and end tabs of differentconfigurations may be employed.

The manner of pasting the liner sheet 25 to the carton blank, however,is pertinent and particularly so because in accordance with the presentinvention glue represented by the broken line areas 30 is disposed inimmediate vicinity of all of the score lines 26 as well as the edges ofthe blank which will be brought together to form its tubular structure.The glue is illustrated herein as extending throughout the full lengthof each of the parallel score lines. However the glue pattern may beintermittent or otherwise varied so long as it is generally in theimmediate area of the score lines and particularly at the ends thereof.Through this expedient close conformity of the liner to the inside ofthe carton is insured and particularly at the corners of the carton.Glue may also be, and is preferably, provided on all of the end tabs ofthe carton so that when the carton is finally set up and the end tabsclosed, the liner will close with them in an orderly and well knownmanner to permit eventual heat sealing of the ends of the carton.

The combined carton and blank as shown in FIG. 3 is then passed througha conventional folding and gluing machine. No details of construction ofwhich are shown herein because the machine insofar as folding a flatblank into a rectangular carton shape is well known in the art. Thefunction of the machine, after first pre-breaking the score lines of thecarton to facilitate folding at these lines, is to carry the cartonthrough folding stages from its original fiat position shown in FIG. 4to the partially folded condition shown in FIG. 5 and then to thefinished fiat fold illustrated in FIG. 6. In FIG. 6, the carton is shownas slightly separated from its final flat fold position to more clearlyillustrate details of construction. The polyethylene coated side of thefolded edge of the liner formed by the folder 13 of FIG. 1 and shown at32 is heated by passing over a flame 33. In practice, the heat isprovided by a plurality of aligned gas burners or other heat source andis sufficient just to soften the polyethylene coating on the marginalfiange 32. A glue of the type used for paperboard cartons also isapplied to a narrow flange 34 by a glue wheel 35 and occupies theposition where it is shown in exaggeration at 36in FIG. 5.

Further advancing of the blank and liner, which it is to be understoodis in continuous motion in the folding machine, swings the panelsadjacent its opposed edges upwardly to a position somewhat as shown inFIG. 5 at which time heat is applied as by a row of gas flame, one ofwhich is shown at 38 to the bead of heat fusible material which wasapplied by the hot melt extruder 14 shown in FIG. 2. Thus when thecarton is completely folded to the position of FIG. 6, the warmed area32 and the fused material 15 will be brought together to form a heatseal of the character sometimes referred to as a flame seal.

After the application of heat to the fusible material 15 as shown inFIG. 5, it is desirable to apply a spray of water by a nozzle 40 to theinside of the liner directly beneath the area where the heat of the sealis brought into contact with the inside of the carton. This water orother suitable coolant directed in a fine fog against the polyethylenesurface of the liner provides sufficient cooling to prevent melting ofthe wax with which the paperboard carton is treated, to preventsoftening of the polyethylene coating on the liner 25 and also toprevent any possibility of adhesion between the material 15 and thepolyethylene coating of the liner in this area should the material beextruded as it is passed between pressure rollers when the carton is inits flat form. The application of pressure between such rollers makes aperfect seal between the plastic coated liner and also serves to perfectthe seal between the flange 34 to which glue has been applied as at 36and a marginal edge 42 of the carton which is not covered by the liner.

The order of application of glue, heat and a coolant above described inconnection with FIGS. 4 to 6 is not critical though it is desirable thatthe coolant be applied just prior to the final folding operation.

We claim:

1. The method of forming a flat fold tubular carton with a liner ofpaper having a coating of heat scalable material on one side thereofwhich comprises folding one edge of a blank of said material back uponitself to present a coated strip along one edge of the uncoated side ofthe blank to extend beyond the edge of a prescored carton blank,securing the liner blank to the prescored carton blank with the coatedside facing inwardly and said strip facing outwardly of the carton blankbeyond an edge thereof, preheating said coated strip and the oppositeedge of said liner, and immediately thereafter folding the blank andliner to form a fiat fold carton with said opposite edge in contact withsaid strip.

2. The method of claim 1 in which a coolant is applied directly to thearea of the liner against which the heated seam will lie when the cartonis in fiat fold form.

3. The method of claim 1 in which the edges of the liner are heated andcoolant is applied directly during folding of the blank and liner.

4. The method of claim 1 in which a fog of liquid coolant is applied tothe area of the liner against which the heated seam will lie when thecarton is in flat fold form.

References Cited in the file of this patent UNITED STATES PATENTS2,095,910 Bergstein Oct. 12, 1937 2,406,061 Cass Aug. 20, 1946 2,423,804Waters July 8, 1947 2,432,053 Waters Dec. 2, 1947 2,438,981 Waters Apr.6, 1948 2,527,692 Andrews Oct 31, 1950 2,776,606 Fischer et al Jan. 8,1957 2,861,002 Britton Nov. 18, 1958 2,950,036 Vergobbi Aug. 23, 1960FOREIGN PATENTS 208,065 Austria Mar. 21, 1960

1. THE METHOD OF FORMING A FLAT FOLD TUBULAR CARTON WITH A OIRE OF PAPERHAVING A COATING OF HEAT SEALABLE MATERIAL ON ONE SIDE THEREOF WHICHCOMPRISES FOLDING ONE EDGE OF A BLANK OF SAID MATERIAL BACK UPON ITSELFTO PRESENT A COATED STRIP ALONG ONE EDGE OF THE UNCOATED SIDE OF THEBLANK TO EXTEND BEYOND THE EDGE OF A PRESCORED CARTON BLANK, SECURINGTHE LINER BLANK TO THE PRESCORED CARTON BLANK WITH THE COATED SIDEFACING INWARDLY AND SAID STRIP FACING OUTWARDLY OF THE CARTON BLANKBEYOND IN EDGE THEREOF, PREHEATING SAID COATED STRIP AND THE OPPOSITEEDGE OF SAID LINER, AND IMMEDIATELY THEREAFTER FOLDING THE BLANK ANDLINER TO FORM A FLAT FOLD CARTON WITH SAID OPPOSITE EDGE IN CONTACT WITHSAID STRIP.